High speed printers, including those of the ion deposition imaging type, are per se well known. In a commercially available ion deposition imaging type of printer, for example, the operative mechanism includes a pair of cylindrical rollers in surface contact with each other and defining a nip therebetween through which the web to be printed on is drawn by the rollers as they rotate. Generally, the upper and larger one of these rollers, which is called the image drum or cylinder, is the one to which the appropriate ion-generated charges and the toner are applied, while the lower and smaller roller, which is called the pressure cylinder, is the one which causes the toner and the paper web passing between the two to be subjected to a high pressure, on the order of 1,000 psi or more, for cold fusion transfixing the toner from the image cylinder to the paper. The image cylinder in this system has its axis oriented perpendicularly to the direction of travel of the paper web, while the pressure cylinder is skewed to the image cylinder and has its axis oriented obliquely to the image cylinder axis and thus also to the direction of travel of the web, with the two axes intersecting each other substantially at the mid-points of the two cylinders.
While the cold fusion transfixing process is highly effective, resulting in the transfer of substantially 100% of the toner image from the image cylinder to the paper, experience has shown that the skewed arrangement of the two cylinders tends to generate speed differentials and temporary longitudinal elongations in the web at various points across the width of the latter. Also, as the web is fed through the nip of the cylinders, i.e., the spiral contact area between the image cylinder and the pressure cylinder, the speed differential across the web generates transverse web stresses along lines oriented obliquely to the direction of travel of the web. This results in the creation of ridges or "soft" wrinkles in the portion of the body of the web just upstream of and approaching the nip, as well as a degree of bagginess at the outer extremities of the various stress areas in the regions of the opposite side edges of the web. Since these "soft" wrinkles and baggy edges increase and accumulate as the web enters the nip, they are then effectively ironed into the web as permanent creases or "hard" wrinkles.